Sodium aluminium sulfate

Sodium aluminium sulfate (CAS 10102-71-3), also known as soda alum or sodium alum, is an inorganic double salt combining sodium, aluminium, and sulfate ions. It carries no E-number designation and is distinct from potassium alum and ammonium alum, though all belong to the alum family.

In water treatment, sodium alum acts as a coagulant by releasing aluminium ions that destabilise suspended particles, enabling their removal through flocculation and sedimentation. In food processing, it functions as an acidulant and leavening component, contributing controlled acidity in baked goods. The pulp and paper industry uses it for pH regulation during sizing processes.

Sodium alum is available in technical and food-grade forms, typically as crystalline solid. Procurement should verify compliance with REACH registration requirements for EU supply. Food-grade material may be assessed against FCC specifications. Standard packaging includes 25 kg bags and bulk quantities depending on supplier.